Step 1: Risk assessment

Machinery manufacturers in the European single market are obliged to offer their customers only safe products. A machine manufacturer must therefore carry out a risk assessment in accordance with the Machinery Directive. This includes identifying the applicable harmonized standards and regulations, determining the limits of the machine, identifying all hazards within each phase of the machine's life, the actual risk assessment and evaluation and the recommended approach to reducing the risk.

Step 2: The safety concept

The safety concept describes the technical measures and ensures the safety of the machinery in accordance with nationally and internationally harmonized standards. A good safety concept resolves the recurring tension between protective devices and productivity. Among other things, it takes into account the use of fixed and movable protective devices, systems for shutting down machines and systems, options for safely switching off electrical energy and pressurized liquids and gases and the detection of workers in hazardous areas.

Step 3: Safety design and selection of components

The aim of the safety design is to achieve a reduction or elimination of hazardous points by working out the necessary protective measures in detail. This applies to new designs as well as to retrofitting or converting machines. Specifically, it involves the design of mechanical, electrical, electronic, software and control systems and the selection of components.

Step 4: Selecting the safety components

In order to be able to select the appropriate components, the performance level (PLr) or safety integrity level (SIL) to be achieved must be determined and verified in accordance with EN ISO 13849-1 / EN IEC 62061. Appropriate calculation tools provide support for this complex process. For example, the 'Safety Calculator PAScal' from Pilz validates the values actually achieved, including the required or specified values PLr or SIL.

Step 5: System integration

The results of the risk assessment and the safety concept are used to implement the selected safety measures. This includes the cooperation and selection of suitable suppliers, procurement of components and implementation of system solutions, project planning of control systems and creation of visualization interfaces, electrical installation of machines and systems, equipment of mechanical protective measures and hydraulic components, inspection and construction of control cabinets as well as training of machine operators and maintenance personnel.

Step 6: Follow-up of the risk assessment

During the risk assessment review, the previous steps are reflected on again: Have the protective measures been implemented correctly? Has safety in connection with the machine control system been designed correctly and implemented in accordance with the safety regulations? Validation is essential to prove that machines are safe. A functional test and fault simulation of the safety system as well as various measurements (e.g. protective conductor, sound level emission) are also part of the review.

Step 7: The operating instructions

Operating instructions are an integral part of the delivery of machines, systems or products. Any error in an instruction manual can lead to legal consequences if it is an instruction error that results in an accident. Safety instructions are a central element of every instruction manual. According to legislation, safety instructions must describe all residual risks that still exist after protective measures against hazards have been taken. The machine manufacturer must also take into account the risks that may arise from "reasonably foreseeable misuse" of the machine by the user. A careful risk assessment is therefore a good basis for drawing up the operating instructions.

The author: Marco Pelizzaro is Divisional Manager Components at Pilz in Meda, Italy.

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Step 8: CE certification

By affixing the CE marking to his product, the manufacturer or distributor ultimately confirms that his product complies with all legal requirements of the Machinery Directive 2006/42/EC and conditions when used as intended. All machines imported from non-EU countries also require a CE marking. The affixing of the CE marking is the sole responsibility of the manufacturer/distributor and does not require official approval.